1. Field of the Invention
This invention relates to improvements in pumping apparatus and more particularly, but not by way of limitation, to a submersible down hole pumping unit for a producing oil and/or gas well, or the like.
2. Description of the Prior Art
The fluid in many producing oil and/or gas wells is elevated to the surface of the ground by the action of a pumping unit or pumping apparatus installed in the lower portion of the well bore. These pumping units are commonly known as down hole pumps, and are activated by a sucker rod string which extends downwardly through the well bore for connecting reciprocating surface equipment with the pump for activation thereof. It is frequently common practice to install the down hole pump in upwardly spaced relation with respect to the fluid reservoir within the well bore, and the pumping action pulls the well fluid into the interior of the well tubing and pushes the accumulated fluid upwardly through the well tubing to the surface of the ground for recovery thereof. In recent times, however, there has been increased activity in the drilling of well bores through a considerably great distance into the earth, as for example twenty thousand feet and more, and it has become necessary or desirable to install the down hole pump within the fluid reservoir. In addition, the use of water flooding for additional fluid recover in oil fields wherein the production of the sub-surface fluid has been somewhat depleted has produced a considerable quantity of down hole fluid in the well bore. As a result it has become essential or necessary to install down hole pumps within the fluid contained within the well bore. This has created a need for pumping units to perform tasks not efficient or practical with the widely used down hole pumps in existence today.
In an effort to solve some of the problems created by the increased depth of the well bores, the sucker rod pumps have been improved by the adaptation of hydraulic drives for the sucker rod but this solution falls short of solving the problem, particularly in efficiency of operation. It is estimated that approximately eighteen percent of the existing producing oil and/or gas wells that are in excess of eight thousand feet deep become economically impractical to be pumped by sucker rod pumping unit due to sucker rod fatigue.
Two major classes of down hole pumps have been developed for this newly arising market, namely, a submersible centrifugal pump manufactured and/or distributed by Reda Pump, Byron Jackson and ODI; and pumps manufactured by Kobe, and which are commonly known as Kobe pumps. The centrifugal pumps are approximately sixteen to twenty percent efficient HP in-put to produce recovered "up-hole" and usually required many stages to pump against the pressure heads involved in eight thousand feet lift operations and greater. The Kobe pump system requires either a double or triple tubing installation, but is efficient only to approximately fifty six percent hydraulic HP in-put to produce lifted out of the well bore.
Other pertinent information generally related to the subject matter is found in the following U.S. patents: Roeder U.S. Pat. No. 3,915,595, issued Oct. 28, 1975, and entitled "Double-Ended Hydraulically Actuated Downhole;" McArthur et al U.S. Pat. No. 3,849,030, issued Nov. 19, 1974, and entitled "Fluid Operated Pump with Opposed Pistons and Valve in Middle;" Lybecker et al U.S. Pat. No. 3,779,671, issued Dec. 18, 1973, and entitled "Hydraulic Driven Piston Pump;" Chenault U.S. Pat. No. 3,374,746, issued Mar. 26, 1948, and entitled "Hydraulically Operated Subsurface Motor and Pump Combination;" Roeder U.S. Pat. No. 4,202,656, issued May 13, 1980, and entitled "Downhole Hydraulically Actuated Pump with Jet Boost;" Brown U.S. Pat. No. 4,120,612, issued Oct. 17, 1978, and entitled "Automatic Pump for Deep Wells;" Heard U.S. Pat. No. 3,918,845, issued Nov. 11, 1975, and entitled "High Volume Hydraulic Recoil Pump;" Pugh U.S. Pat. No. 3,922,116, issued Nov. 25, 1975, and entitled "Reversing Mechanism for Double-Action Hydraulic Oil Well Pump;" Spears U.S. Pat. No. 4,332,533, issued June 1, 1982, and entitled "Fluid Pump;" Gilbertson U.S. Pat. No. 4,320,799, issued Mar. 23, 1982, and entitled "Oil Well Pump Drive-in Unit;" Roeder U.S. Pat. No. 3,865,516, issued Feb. 11, 1975, and entitled "Fluid Actuated Down-Hole Pump;" Roeder U.S. Pat. No. 3,957,400, issued May 18, 1976, and entitled "Double-Ended Hydraulically Actuated Down-Hole Pump;" Roeder U.S. Pat. No. 3,650,640, and entitled "Downhole Pump Assembly Having Engines Spaced Apart By a Production Pump;" Roeder U.S. Pat. No. 3,517,741, issued June 30, 1970, and entitled "Hydraulic Well Pumping System;" Roeder U.S. Pat. No. 3,453,963, issued July 8, 1969, and entitled "Downhole Fluid Activated Pump Assembly;" Carrens U.S. Pat. No. 4,293,287, issued Oct. 6, 1981 and entitled "Reversing Valve Assembly for a Fluid Operated Well Pump;" Roeder U.S. Pat. No. 4,268,227, issued May 19, 1981, and entitled "Downhole, Hydraulically-Actuated Pump and Cavity Having Closed Power Fluid Flow;" Jensen U.S. Pat. No. 4,234,294, issued Nov. 18, 1980, and entitled "Deep Well Hydraulic Pump System Using High Pressure Accumulator;" Roeder U.S. Pat. No. 4,118,154, issued Oct. 3, 1978, and entitled "Hydraulically Actuated Pump Assembly;" Ferguson U.S. Pat. No. 3,162,143, issued Dec. 22, 1964, and entitled "Well Pumps;" Schmidt U.S. Pat. No. 3,164,102, issued Jan. 5, 1965, and entitled "Oil Well Pump;" Gage U.S. Pat. No. 3,910,730, issued Oct. 7, 1975, and entitled "Oil Well Pump;" Roeder U.S. Pat. No. 3,865,516, issued Feb. 11, 1975, and entitled " Fluid Actuated Down-Hole Pump;" Russell U.S. Pat. No. 4,087,206, issued May 2, 1978, and entitled "Subsurface Pumping Unit Incorporating Heavy Duty Reversing Valve and Method of Operating;" Sprenger U.S. Pat. No. 4,082,483, issued Apr. 4, 1978, and entitled "Oil Well Pump;" Roeder U.S. Pat. No. 4,080,111, issued Mar. 21, 1978, and entitled "High Volume, Double Acting Downhole Pump;" Gage U.S. Pat. No. 4,013,387, issued Mar. 22, 1977, and entitled "Oil Well Pump;" David U.S. Pat. No. 4,003,678, issued Jan. 18, 1977, and entitled "Fluid Operated Well Turbopump;" Soberg U.S. Pat. No. 3,941,516, issued Mar. 2, 1976, and entitled "Waterwell Pump Assembly;" Roeder U.S. Pat. No. 3,953,155, issued Apr. 27, 1976, and entitled "Pump Plunger;" Watson U.S. Pat. No. 3,965,983, issued June 29, 1976, and entitled "Sonic Fluid Level Control Apparatus;" Onal U.S. Pat. No. 3,981,626, issued Sept. 21, 1976, and entitled "Down Hole Pump and Method of Deep Well Pumping;" Scott U.S. Pat. No. 3,986,552, issued Oct. 19, 1976, and entitled "Pumping System for High Viscosity Oil;" Douglas U.S. Pat. No. 3,861,471, issued Jan. 21, 1975, and entitled "Oil Well Pump Having Gas Lock Prevention Means and Method of Use Thereof;" Saruwatari U.S. Pat. No. 4,114,375, issued Sept. 19, 1978, and entitled "Pump Jack Device;" Sarawatari U.S. Pat. No. 4,047,384, issued Sept. 13, 1977, and entitled "Pump Jack Device;" Smith U.S. Pat. No. 2,564,285, issued Aug. 14, 1951, and entitled "Pneumatic-Hydraulic System for Operating Well Pumping Equipment;" Aller et al U.S. Pat. No. 2,645,899, issued July 21, 1953, and entitled "Hydropneumatic Pumping Unit;" Becker U.S. Pat. No. 2,808,735, issued Oct. 8, 1957, and entitled "Automatic Counterbalance for Well Pumping Apparatus;" Jones U.S. Pat. No. 2,887,093, issued May 19, 1959, and entitled "Hydraulically Operated Pumping Apparatus;" and Johnston U.S. Pat. No. 2,247,238, issued June 24, 1941, and entitled "Hydropheumatic Pumping System." These devices, however, do not satisfy the needs nor overcome the disadvantages of the present available equipment as hereinbefore set forth.